G3408 and G3412 Engines Caterpillar

Connecting Rods And Pistons

Use the 7M-3978 Ring Expander to remove piston rings or install piston rings.

Use the 5P-3526 Piston Ring Compressor to install pistons into the cylinder block.

Tighten the connecting rod nuts in the step sequence that follows:

1. Apply 4C-5593 Anti-Seize Compound to the threads of the bolts and the contact surfaces of the bolt head.

2. Tighten all nuts to the following torque.

   Torque for nuts ... 82 ± 8 N·m (60 ± 6 lb ft)

3. Put an alignment mark on each cap and bolt.

4. Tighten the nuts from the mark to the following value.

   Angle from the mark. ... 120 ± 5 degrees

Connecting Rod Bearings

The connecting rod bearings fit tightly in the bore in the rod. If the bearing joints or backs are fretted, check the bore size. This can be an indication of wear because of a loose fit.

Connecting rod bearings are available with 0.63 mm (0.025 inch) and 1.27 mm (0.050 inch) smaller inside diameter than the original size bearing. These bearings are for crankshafts that have been ground smaller than the original size.

Main Bearings

Main bearings are available with a larger outside diameter than the original size bearings. These bearings are available for the cylinder blocks with the main bearing bore that is made larger than the bores' original size. The size that is available has a 0.63 mm (0.025 inch) outside diameter that is larger than the original size bearings.

Cylinder Block

Illustration 1	g00294303
1P-3537 Dial Bore Gauge Group

If the main bearing caps are installed without bearings, the bore in the block for the main bearings can be checked. Tighten the nuts that hold the caps to the torque that is shown in the Specifications. Alignment error in the bores must not be more than 0.08 mm (0.003 inch). Refer to the Special Instruction, SMHS7606.

Projection Of Cylinder Liners

Illustration 2	g00332134
Holding the top plate to the cylinder block (1) 3H-0465 Push Puller Plate. (2) 1P-2396 Puller plate. (3) 2F-0126 Seal. (4) Top plate.

Use the following steps to check the liner projection above the top plate.

1. Ensure that the top plate (4) and the cylinder liner flange are clean.

2. Install a new spacer plate gasket.

3. Install the cylinder liners in the cylinder block without seals or bands.

4. Use 3/4 - 16 NF bolts that are 76.2 mm (3.0 inch) long. Use two 2F-0126 Seals (3) on each bolt. These seals will hold the top plate (4) to the cylinder block. Install two bolts with seals (3). Install the bolts on each side of the cylinder liner. Use the following four steps to tighten the bolts.

   Tighten the bolts to the following torque. ... 14 N·m (10 lb ft)

   Tighten the bolts again to the following torque. ... 35 N·m (26 lb ft)

   Tighten the bolts again to the following torque. ... 70 N·m (52 lb ft)

   Tighten the bolts again to the following torque. ... 95 N·m (70 lb ft)

   Note: Install two bolts with washers on each side of each cylinder liner. Install the bolts along the complete length of the top plate. This will keep the installation and removal of the bolts and washers to a minimum as each liner is checked.

5. Use the following items to hold the liner down.
   • 1P-2396 Puller Plate (2)

   • three 3H-0465 Push Puller Plates (1)

   • 8B-7548 Push-Puller Tool Group (6)

   • two 3/4 - 16 NF bolts 177.8 mm (7.0 inch) in length

6. Use the following four steps to tighten the bolts evenly.

   Tighten the bolts to the following torque. ... 7 N·m (62 lb in)

   Tighten the bolts again to the following torque. ... 20 N·m (15 lb ft)

   Tighten the bolts again to the following torque. ... 35 N·m (26 lb ft)

   Tighten the bolts again to the following torque. ... 70 N·m (52 lb ft)

   The distance from the bottom edge of the 8B-7548 Push Puller Tool Group (6) to the top plate must be equal on both sides of the cylinder liner.

Show/hide table



Illustration 3	g00332135
Measuring the liner height projection (5) Dial indicator. (6) 8B-7548 Push Puller Tool Group. (7) 1P-2402 Gauge Body .

7. The 8T-0455 Liner Projection Tool Group can be used to measure the liner projection. The Special Instruction, SMHS7727 is included with this group.

8. Mount the indicator (5) in the 1P-2402 Gauge Body (7). Zero the indicator (5) by using the back of the 1P-5507 Gauge Block .

9. Record measurements for each cylinder.

10. Find the average reading. Add the four readings for each cylinder and divide the sum of the readings by four.

Flywheel And Flywheel Housing

Face Runout (Axial Eccentricity) Of The Flywheel Housing

Illustration 4	g00319523
8T-5096 Dial Indicator Group

If you use any other method except the method that is given here, always remember that the bearing clearance must be removed in order to receive the correct measurements.

1. Fasten a dial indicator to the flywheel so the anvil of the dial indicator will contact the face of the flywheel housing.

2. Put a force on the crankshaft toward the rear before the dial indicator is read at each point.

Show/hide table



Illustration 5	g00294392
Checking face runout of the flywheel housing (A) Bottom. (B) Right side. (C) Top. (D) Left side.

3. Turn the flywheel while the dial indicator is set at 0.0 mm (0.00 inch) at location (A). Read the dial indicator at locations (B), (C) and (D) .

4. The difference between the lower measurements and the higher measurements that are performed at all four points must not be more than 0.30 mm (0.012 inch), which is the maximum permissible face runout (axial eccentricity) of the flywheel housing.

Bore Runout (Radial Eccentricity) Of The Flywheel Housing

Show/hide table



Illustration 6	g00294390
8T-5096 Dial Indicator Group

1. Fasten a dial indicator to the flywheel so the anvil of the dial indicator will contact the bore of the flywheel housing.

Show/hide table



Illustration 7	g00294394

2. While the dial indicator is in the position at location (C), adjust the dial indicator to 0.0 mm (0.00 inch). Push the crankshaft upward against the top of the bearing. Refer to the illustration 7. Write the measurement for bearing clearance on line 1 in column (C) .

   Note: Write the measurements for the dial indicator with the correct notations. This notation is necessary for making the calculations in the chart correctly.

3. Divide the measurement from Step 2 by two. Write this number on line 1 in columns (B) and (D) .

4. Turn the flywheel.

5. Put the dial indicator at point (A). Adjust the dial indicator to 0.0 mm (0.00 inch).

Show/hide table



Illustration 8	g00294392
Checking bore runout of the flywheel housing (A) Bottom. (B) Right side. (C) Top. (D) Left side.

6. Turn the flywheel counterclockwise in order to put the dial indicator at point (B). Write the measurements in the chart.

7. Turn the flywheel counterclockwise in order to put the dial indicator at point (D). Write the measurement in the chart.

8. Add the lines together in each column.

9. Subtract the smaller number from the larger number in line III in column B and column D. Place this number on line III. The result is the horizontal eccentricity (out of round). Line III in column C is the vertical eccentricity.

Show/hide table



Illustration 9	g00294396
Graph for total eccentricity (1) Total vertical eccentricity. (2) Total horizontal eccentricity. (3) Acceptable value. (4) Unacceptable value.

10. Find the point of intersection of two lines on the graph. One of the lines is the line for vertical eccentricity. The other line is the line for horizontal eccentricity.

11. The bore is in alignment if the point of intersection is in the range that is marked "Acceptable". The flywheel housing must be changed if the point of intersection is in the range that is marked "Unacceptable".

Face Runout (Axial Eccentricity) Of The Flywheel

Show/hide table



Illustration 10	g00294398
Checking face runout of the flywheel

1. Refer to illustration 10 and install the dial indicator. Always put a force on the crankshaft in the same direction before the dial indicator is read. This will remove any crankshaft end clearance.

2. Set the dial indicator to read 0.0 mm (0.00 inch).

3. Turn the flywheel at intervals of 90 degrees and read the dial indicator.

4. Take the measurements at all four points. Find the difference between the lower measurements and the higher measurements. This value must not exceed 0.15 mm (0.006 inch). This is the maximum permissible face runout (axial eccentricity) of the flywheel.

Bore Runout (Radial Eccentricity) Of The Flywheel

Illustration 11	g00294400
Checking bore runout of the flywheel (1) 7H-1945 Holding Rod. (2) 7H-1645 Holding Rod. (3) 7H-1942 Dial Indicator. (4) 7H-1940 Universal Attachment .

1. Install the 7H-1942 Dial Indicator (3). Make an adjustment of the 7H-1940 Universal Attachment (4) so that the dial indicator makes contact on the flywheel.

2. Set the dial indicator to read 0.0 mm (0.00 inch).

3. Turn the flywheel at intervals of 90 degrees and read the dial indicator.

4. Take the measurements at all four points. Find the difference between the lower measurements and the higher measurements. This value must not exceed 0.15 mm (0.006 inch). This is the maximum permissible bore runout (radial eccentricity) of the flywheel.

Show/hide table



Illustration 12	g00294401
Checking the runout of the flywheel clutch pilot bearing bore

5. The runout (eccentricity) of the bore for the pilot bearing for the flywheel clutch must not exceed 0.13 mm (0.005 inch).

Vibration Damper

Damage to the vibration damper or failure of the vibration damper will increase vibrations. This will result in damage to the crankshaft.

Make an inspection of the outer case (1) for dents or other damage to the vibration damper. Dents in the outer case can cause a failure of the vibration damper.

Illustration 13	g00319238
Vibration damper (1) Outer case of the vibration damper.